Run macos job on `uv` and newer `actions@v4`

.github/workflows/ci.yml

@@ -134,13 +134,11 @@ jobs:
         ]
 
     steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-
-      - name: Setup python
-        uses: actions/setup-python@v2
+      - uses: actions/checkout@v4
+      - name: 'Install uv + py-${{ matrix.python-version }}'
+        uses: astral-sh/setup-uv@v6
         with:
-          python-version: '${{ matrix.python }}'
+          python-version: ${{ matrix.python-version }}
 
       - name: Install the project w uv
         run: uv sync --all-extras --dev